Mixed explosive compositions

Most explosive and propellant compositions contain a mixture of components so as to optimize their performance. Some of the components may not contribute to the heat liberated and may not even contain oxygen. These materials may however, contribute to the gaseous products and reduce the actual temperatures obtained on detonation of the explosive or burning of the propellant. An example of a typical mixed explosive composition is one which contains 60% RDX and 40% TNT, and where the heat of explosion Q has been optimized. In order to calculate the values of Q and V for this composition the oxygen balance and the reaction for decomposition need to be determined. But even before these can be calculated the atomic composition of the mixture must first be established. 

The reaction for the decomposition products of the mixed explosive composition can be determined by applying the modified Kistia-kowsky Wilson rules as shown in Table 5.16. 

The heat of explosion for the mixed explosive composition can now be calculated from the heat of formation for the explosive components and the heat of formation for its products as shown in Figure 5.8. 

The volume of the gaseous products liberated during an explosion by the mixed explosive composition at stp can be calculated from the equation for explosion as shown in Reaction 5.12. 

From Reaction 5.12 it can be seen that 0.03755 mol of gas is produced from 1 g of mixed explosive composition, which will occupy a volume of 0.841 dm3 g 1 as shown in Equation 5.22 ... 

This explosives volatile nature can be overcome to some extent by enclosing the mixed explosive composition in something impervious to gasoline. Large trash bags would serve this purpose. The explosive would need to be used quickly, however, as this measure would not be enough to ensure the explosives loss of sensitizer to evaporation. Better explosive composition can be had, but this one would work and is powerful ... 

The mixed explosive composition containing 60" . RiyX with 40% TNT therefore has a (7 value of4720 kJ kg. a 1 value of 0.841 dm g nd a power inde.x equal to 147%. 

The mixed explosive composition containing 60% RDX with 40% TNT therefore has a Q value of 4684 kJkg a V value of 841dm kg a power index equal to 143.59% and a TNT equivalence of 1.30. 

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